1. Field of the Invention
The present invention relates, in general, to a multiplexer having a monoblock dielectric structure capable of processing multi-band signals, and, more particularly, to a multiplexer which has a monoblock dielectric structure capable of transmitting and receiving signals composed of various band components through a common antenna by extending a duplexer that performs transmission and reception through a single antenna.
2. Description of the Related Art
With the development of communication technology, the use of mobile communication terminals exploiting various frequencies has rapidly increased, and the use of high frequencies for mobile communication has gradually increased to improve the type and quality of services provided by mobile communication terminals.
Recent mobile communication technologies are classified into first, second and third generation technologies according to the amount and type of content that can be transmitted. Various high frequencies have been used for a variety of types of services such as Wireless Broadband Internet (Wibro) enabling the fast Internet to be used while moving from place to place.
Generally, a duplexer is a principal part of a mobile communication terminal, and provides a function of passing therethrough only signals of a specific frequency band of a transmission filter and a reception filter, via a combined transmission (TX)/reception (RX) antenna. Duplexers may be classified into various types, but require the realization of a small size and a light weight as essential conditions so as to improve the portability of mobile communication terminals. In order to satisfy these conditions, monoblock dielectric duplexers have been widely used.
Such a monoblock dielectric duplexer is designed such that a plurality of resonant holes forms the filters of TX/RX stages on a dielectric block and the frequency characteristics of the filters are exhibited by conductive patterns around the holes. Such a monoblock dielectric duplexer is advantageous in that a process for manufacturing the duplexer can be simplified, can be easily implemented and can be designed to have a small size. However, a monoblock dielectric duplexer is disadvantageous in that, since it is used only in a single frequency band, duplexers having different frequency bands must be used in multiple bands, so that the size of the system increases and the number of processes used to manufacture the duplexer increases, thus increasing the costs of manufacturing the system.
Furthermore, such a conventional monoblock dielectric duplexer is problematic in that, when band-pass filters having different frequency processing bands are used to process multi-band signals, an E-H field formed in a first band-pass filter is not transferred to a subsequent band, thus making it impossible to increase the number of channels that can be processed.